Splunk Enterprise: Improper Authentication
CVE-2026-76338 is a high-severity improper authentication vulnerability in Splunk Enterprise from Splunk, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 10.4.2, 10.2.6, 10.0.9 as the first without the flaw, so updating Splunk Enterprise to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.47% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Splunk Enterprise to 10.4.2 or 10.2.6 or 10.0.9 or 9.4.14, whichever matches your release line, or a later version.
- Update Splunk to 9.4.14 or 10.0.9 or 10.2.6 or 10.4.2, whichever matches your release line, or a later version.
- Read the advisory on advisory.splunk.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Splunk | Splunk Enterprise | 10.4 up to, but not including, 10.4.2; 10.2 up to, but not including, 10.2.6; 10.0 up to, but not including, 10.0.9; 9.4 up to, but not including, 9.4.14 | 10.4.2, 10.2.6, 10.0.9, 9.4.14 |
| Splunk | Splunk | 9.4.0 up to, but not including, 9.4.14; 10.0.0 up to, but not including, 10.0.9; 10.2.0 up to, but not including, 10.2.6; 10.4.0 up to, but not including, 10.4.2 | 9.4.14, 10.0.9, 10.2.6, 10.4.2 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (cisco.com).
Official description
In Splunk Enterprise versions below 10.4.2, 10.2.6, 10.0.9, and 9.4.14, an unauthenticated user who has access to a trusted distributed search private key could forge an administrative session token, access all relevant data, affect system integrity, and disrupt service availability. The vulnerability is possible because the distributed search authentication token endpoint does not require a signed request to identify a configured search peer, allowing the request to fall back to shared local key material. For more information see About distributed search (https://help.splunk.com/en/splunk-enterprise/administer/distributed-search/10.4/overview-of-distributed-search/about-distributed-search) and authentication.conf (https://help.splunk.com/en/splunk-enterprise/administer/admin-manual/10.4/configuration-file-reference/10.4.2-configuration-file-reference/authentication.conf) in Splunk documentation.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Authentication
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.
How developers prevent this class of flaw
- Use an authentication framework or library such as the OWASP ESAPI Authentication feature.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in Splunk Enterprise
- 9.9 Critical severity
- 9.8 Critical severity
- 8.8 High severity
- 9.9 Critical severity
- 8.8 High severity
- 7.2 High severity
Recent Improper Authentication vulnerabilities
- 8.2 High severity
- 10.0 Critical severity
- 7.4 High severity
- 8.8 High severity
- 9.8 Critical severity
- 7.6 High severity
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